RotorMotor

iTrader: (5)

hey. i wanted some input as to what i should do regarding my cat. i have a knightsports metalit highflow cat which is going to be used with my 20b.... since the motor takes up so much extra room i have to use spaace wisely. that means most likely getting rid of the airpump to for air filters, intake piping etc... anyway, i wanted to ask about running my cat without an airpump... what problems i would run into (the cat that im using has a fine metal mesh...ill try to post a picture) so it looks like it could clog easily. i read a few posts about electric airpumps and it seems that they just burn out after a few minutes of use. thanks, heath

1234rotor

iTrader: (1)

In reality, an airpump is kind of like a band-aid to pass emissions inspection. They pump fresh air into the exhaust to show a lower fuel content ratio.

I say you do without it, or, if you are that concerned about it possibly burning out your nice cat (because higher fuel ratios make the cat glow hotter), run a mid pipe resonator inbetween emissions.

RotorMotor

iTrader: (5)

yeah im just worried about clogging this car since the mesh is so fine... but i picked this one as it supposedly flows almost as well as a MP.

1234Rotor: yes im comcerned with cooking my cat... but the whole reason i have it is so it can be used 24/7 on the car... i dont want to pump any more garbage into the atmosphere than i already am... plus running without a cat makes my clothes stink!

maxcooper

I believe the air injection makes the cat hotter, since it allows the fuel that is left int he exhaust to burn. So, I don't believe that omitting the air pump can make the cat melt. However, perhaps it ends up being too cool, and fails to burn off some of the exhaust content which leaves you with a clogged cat.

I'll be running a cat with no air pump on my new setup. I am not expecting any major issues, but only time will tell. I thought of running one of those electric air pumps from a Corvette, but I heard they burn out quickly, too. Perhaps there is a more durable electric air pump that could be used.

-Max

Sesshoumaru

iTrader: (1)

ran no pump on FC for 10,000 so far

FD has no air pump but only has about 700.

voids warranty

3 inch hiflow

DaleClark

iTrader: (55)

I'm also wondering if it would be possible to use the airpump off an RX-8 - it uses an electric air pump. From what I've heard, it's pretty beefy - serious power wires running to it.

Big thing would be finding an electric air pump that's actually reasonable - doesn't draw a ton of current, isn't super loud, and is relatively compact.

Of course, it also begs the question as to how necessary the air pump really is, especially if you're mainly concerned with reducing stinkyness and a little boost control.

Dale

JONSKI

You might as well not even have a catalytic converter without an airpump. There's no way an FD will pass emissions without an airpump.

maxcooper

Mine won't pass emissions with the cat, but it should smell a lot better. With my last setup, cyclists would fall off their bikes and pedestrians would wilt as I passed (no, not really). The presence of a cat might encourage the po-po to go a little easier on you if they stop you and decide to inspect your car, too. Hey, at least I am trying! I'd actually like to get a setup that would pass the sniffer test (even though it would fail the visual). An electric air pump will be needed for that.

There was an article in one of the magazines about an FD that Rotary Performance in Texas did for a customer a few years ago that had a single turbo, electric air pump, and would actually pass the emissions test (IIRC). That was pretty cool.

-Max

AntiVenom7

i have been running a high flow cat with no air pump for about 7-8K miles on my FD. Still running strong. I ran a high-flow instead of a midpipe to try and avoid boost creep. however as soon as i port my wastegate and make the switch to a PowerFC next month I am gonna change out to a midpipe.

-Josh

Tom93R1

iTrader: (2)

Cat WILL NOT CLOG without the air pump. Also the purpose of the air pump is not to dilute the exhaust to make it look cleaner, that is the biggest load of BS I have ever heard when it comes to the air pump.

The purpose of the air pump is to add oxygen to the exhaust gasses to aid in combustion. combustion requires both fuel and oxygen. Since the rx7 runs rich you need more oxygen, hence the air pump. Without the air pump you will burn off some of the catalysts. Your exhaust will definately smell better than with a mid pipe but it will not be as clean as with the air pump. It is better than nothing though.

You can use any electric air pump you want, it is just a question of inding a place to mount it and how to wire it up. I imagine it wouldnt be too difficult to figure out the stock air pump turn on circuit to make it come on line either.

RotorMotor

iTrader: (5)

so the cat wont clog... i wont get the *best* emmisions (better than nothing in my oppinion though)... but your saying that it may get so hot that it "burns off" a good amount of the catalyst in the cat?

Rhode_Dog

But that cat is differn't than a normal catalytic converter. Didn't the Knightsport's one come in a air pump and non air pump ready model?

RotorMotor

iTrader: (5)

not that i saw... i think they have some sort of racing version, but i forget what the difference is.... anyway, IIRC there is no version that does not use a cat (but dont quote me on that factI

maxcooper

No, I think he means that the exhaust will be the "cleanest" if you do have an air pump. It won't be as clean without the air pump. It is worded strangely, but I think the intent was basically "without air pump, you only burn SOME (as opposed to MORE or ALL) of the bad stuff out of the exhaust".

Everyone needs to clear their minds of the idea that the air injection somehow "cools" the cat. It really has the opposite effect -- add air and the residual fuel in the exhaust will burn in the cat, making the cat hotter.

-Max

Tom93R1

iTrader: (2)

Thanks, yeah that is what I meant. I dont know why I said "catalysts".

RomeoFC3S

hi u guys, fresh rotary guy here..

here in canada we have no emission test.. what can i do with my fc t2?
what are some advantages i can do with it or shave off?? thank you!

su_maverick

you might want to check the 2nd gen board for that one, this is a fd board...not trying to be harsh